/*
    弹出小球
*/
#backgroundBtn{
    position: fixed;
    left: 0;
    top: 0;

}
#popping_close,#popping_left,#popping_right{
    width: 4.5em;
    height: 4.5em;
    background-color: pink;
    border-radius: 50%;
    position: absolute;
}
#popping_close{
    top: 9em;
}
#popping_left{
    top: 9em;
    left: 6em;
}
#popping_right{
    top: 9em;
    left: -5em;
}
.change_close{
    animation: popping_close 0.2s linear forwards;
}
.change_left{
    animation: popping_left 0.6s linear forwards;
}
.change_right{
    animation: popping_right 0.6s linear forwards;
}
.change_close_close{
    animation: popping_close_close 0.1s linear forwards;
}
.change_close_left{
    animation: popping_close_left 0.4s linear forwards;
}
.change_close_right{
    animation: popping_close_right 0.4s linear forwards;
}
@keyframes popping_left{
    0%{
        left: 6em;
        top: 9em;
    }
    30%{
        left: 1em;
        top: 1em;
    }
    50%{
        left: -6em;
        top: -7em;
    }
    60%{
        left: -4.5em;
        top: -5.5em;
    }
    75%{
        left: -5.5em;
        top: -6.5em;
    }
    100%{
        left: -5em;
        top: -6em;
    }
}
@keyframes popping_right{
    0%{
        left: -5em;
        top: 9em;
    }
    30%{
        left: 1em;
        top: 1em;
    }
    50%{
        left: 6em;
        top: -7em;
    }
    60%{
        left: 5.5em;
        top: -5.5em;
    }
    75%{
        left: 6.5em;
        top: -6.5em;
    }
    100%{
        left: 5em;
        top: -6em;
    }
}
@keyframes popping_close{
    0%{
        top: 9em;
    }
    100%{
        top: 0em;
    }
}
@keyframes popping_close_left{
    0%{

        left: -5em;
        top: -6em;
    }
    100%{
        left: 6em;
        top: 9em;
    }
}
@keyframes popping_close_right{
    0%{
        left: 5em;
        top: -6em;
    }
    100%{

        left: -5em;
        top: 9em;
    }
}
@keyframes popping_close_close{
    0%{
        top: 0em;
    }
    100%{
        top: 9em;
    }
}